Atoms and Ions
- Atoms are electrically neutral
- # of protons = # of electrons
- Ions have a different number of protons and electrons
- Ions can either be positve (lose electrons) or negative (gain electrons)
- Cation = positive ion
- Anion = Negative ion
- Determine how many electrons each of the ions have and what type of ion they are:
Ca2+ = lost 2e-/cation
F- = gained 1 e-/anion
H+ = lost 1 e-/cation
Ag+ = lost 1e-/cation
H- = gained 1e-/anion
N3- = gained 3e-/ anion
- Determine how many protons, neutrons and electrons the following substances have:
76As3-/ p+ = 33/ n0= 43/ e- = 36
201Au+/ p+ = 79/ n0= 122/ e- = 78
56Fe3+/ p+ = 26/ n0= 30/ e- = 23
Bohr Diagrams for Ions
- Draw the energy level or Bohr Diagram for the following ions:
Ca2+ 8e-/8e-/2e-
Li+ 2e-
F- 8e-/2e-
O2 8e-/2e-
P3- 8e-/8e-/2e-
Chemical Bonds
- A bond is an electrostatic attraction between particles
- Bonds occur as elements try to achieve Noble gas electron configuration
- Noble gases (usually) do not form compounds or bonds
- In Noble gases the outermost energy levels have stable octets
Lewis Dot Structures
- Atoms can be represented by dot diagrams
- Dots represent electrons
- Only valence electrons are shown
- Write the atomic symbol for the atom
- This represents the nucleus and filled inner energy levels
- One dot is used to represent outer energy levles
- One e- is placed in each orbital before any pairing occurs
- Beginning with the 5th e-, pairing can occur up to a maximum of 8e-
- Below: Electron dot diagrams for different elements
Ionic Bonds
- Electrons are transferred from metal to non-metal
- No dots are shown on metal
- "Charged" species are written in brackets
- Example: Sodium Chloride
This video touches upon Ionic dot diagrams:
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